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I'm using the Apple AVCam code with AVCamCaptureManger to capture a still image. I don't display any camera views to the user, the image is just automatically taken behind the scenes without the user's involvement. However, it still plays a shutter sound when I call [captureManger captureStillImage] and I don't want it to play a shutter sound.
There are many apps in the AppStore that "secretly" take a picture without a shutter sound, so I'm sure it's possible to somehow mute this sound. If I can't mute this sound directly, is there anyway to adjust not the volume of the phone, but the volume of my app itself (the output volume of the app)?
You have to use an AVCaptureVideoDataOutput if you want to avoid the shutter sound. Note that covertly capturing images is against App Store policy. You need to make sure you user is told in some way that your taking a picture.
来源：https://stackoverflow.com/questions/8621252/muting-avcapture-shutter-sound-on-iphone